The current state-of-the-art for video encoding is the ITU-T H.264/AVC video coding standard. It defines a number of different profiles for different applications, including the Main profile, Baseline profile and others.
There are a number of standards for encoding/decoding images and videos, including H.264, that use block-based coding processes. In these processes, the image or frame is divided into blocks, typically 4×4 or 8×8, and the blocks are spectrally transformed into coefficients, quantized, and entropy encoded. In many cases, the data being transformed is not the actual pixel data, but is residual data following a prediction operation. Predictions can be intra-frame, i.e. block-to-block within the frame/image (also called spatial predication), or inter-frame, i.e. between frames (also called motion prediction).
A problem that arises in connection with encoding and decoding is that intra-coded spatial prediction relies upon reconstructed pixels in neighbouring blocks within the image. As a result the errors in the reconstructed values of an intra-coded block have a negative impact on rate-distortion performance.
It would be advantageous to provide for an improved encoder, decoder and method of encoding or decoding.
Similar reference numerals may have been used in different figures to denote similar components.